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Why sewage pollution is becoming an ecological issue
Blog...Why sewage pollution is becoming an ecological issue

Why sewage pollution is becoming an ecological issue

Ecology News
arial view of water treatment facility
In this article we’ll explore why sewage pollution is such a problem, what is causing the issue, and why England in particular has come under the spotlight for its sewage situation.
Ecology News
arial view of water treatment facility

Clean water is something that a lot of us take for granted, but recent headlines have brought to light the dirty truth about sewage pollution in our water bodies. 

Years of underfunding and deregulation have pushed sewage systems to crisis point, and now countries such as the UK are faced with the challenge of cleaning up their act, and preventing the UK’s bodies of water from deteriorating even further. 

👉 In this article we’ll explore why sewage pollution is such a problem, what is causing the issue and why England in particular has come under the spotlight for its sewage situation.

How does sewage affect the environment?

Raw or partially treated sewage is harmful when it’s released into the environment. It needs to be properly treated before it can be safely disposed of. Otherwise it can contaminate water, cause pollution, harm wildlife, and even result in the spread of disease.

So how exactly does sewage cause this harm?

Algae blooms

One of the reasons that it’s so harmful is because when sewage enters our waterways, it introduces large amounts of nutrients into the water - something that’s known as eutrophication. The introduction of nitrogen and phosphorus are especially problematic as they stimulate the growth of plants and algae. 

Algae in particular can be harmful for the ecosystem. For example, algae blooms can block out the light that other plants in the waterbody need for photosynthesis. This eventually causes plants in the water to die, which leads to a buildup of bacteria who thrive on the dead organic material. The buildup of bacteria reduces the levels of oxygen, which in turn kills fish and other aquatic organisms. 

👉 Some algae blooms - for example blue green cyanobacteria blooms - can even produce toxins that are not only harmful for fish and insects, but also harmful to larger animals too, such as dogs and humans.

algae bloom in river

Delicate ecosystems

Aquatic ecosystems are often delicate and can be easily upset by imbalances. For example, one of the most severely affected groups by algae blooms are freshwater insects who depend on high levels of oxygen in the water for survival. When their numbers decline this also has a knock on effect for the wider waterbody. Fish depend on freshwater insects for food and so when insect numbers decline their food source also declines - causing starvation or forcing fish to migrate. This example illustrates how an impact on one species within an environment can disrupt the wider ecosystem. 

Many other different aquatic environments are also adversely impacted by the presence of contaminants. Coral reefs for example are particularly vulnerable to contamination, as are coastal mangroves and salt marshes. The presence of sewage in these environments can result in their decline.

freshwater fish in river

Harmful chemicals and diseases

And it’s not just nitrogen and phosphorus that pose a problem, sewage contains a whole variety of harmful chemicals, bacteria and even diseases - just think of all the different things that are flushed down the toilet and our drains. Herbicides, pesticides, hormones, medications, paints, solvents, human waste etc. This can pose a significant threat to humans and wildlife if allowed to enter our waterways untreated. 

Sewage pollution can also allow diseases such as cholera diarrhea, dysentery, hepatitis A, typhoid and polio to spread. 

👉 Did you know? Wastewater is a carrier of disease. According to the World Health Organization (WHO), over 3.4 million people die each year as a result of waterborne diseases.

someone in hospital bed with drip inserted into their hand

Effects on coastal regions and poor communities

Although sewage pollution impacts everyone, it’s primarily those living in coastal or river based regions who are the most vulnerable - this is exacerbated even further when the communities involved are poorer. 

Sewage directly damages the environment but it also diminishes the value of these regions by making them unfit for tourism or recreational purposes, or harming the local population's ability to live off the area.

Ultimately sewage entering our water bodies is problematic and destructive for a variety of different reasons. It kills wildlife, destroys ecosystems, contaminates drinking water, impacts public health, and damages economies that are reliant on water bodies for tourism purposes or subsistence (e.g. fish farming).

What  are the causes of sewage pollution?

👉 Did you know? Over 80% of global sewage is dumped into the seas without adequate treatment. 

So how exactly does sewage end up in our bodies of water?

Inadequate infrastructure

A lot of the world’s sewage drains and pipeline networks were built in the early 19th and 20th centuries, when populations were lower. This means that they’re not always up to the job when it comes to handling the amount of sewage that our expanding populations produce.

Ship dumping

Although a lot of jurisdictions have regulations that control the distance that ships must be from coastline before dumping sewage, the level of treatment that sewage must first undergo, and the volume of sewage that can be dumped - a lot of coastal areas lack enforcement mechanisms. 

👉 Around 20 million people sail on cruise ships every year, resulting in around 11 billion liters of sewage.

Inadequate treatment facilities

Sewage pollution may also be caused by improper sewage treatment facilities. Some facilities are unable to cope with large amounts of sewage. They may also suffer from lack of repair or maintenance. 

In some countries and areas it may not even be that the treatment facilities are inadequate - there might not be any at all. Communities in low income countries may not have access to sanitation facilities or clean drinking water altogether. 

👉According to the WHO 46% of the world’s population don’t have access to adequate sanitation services.

In areas where there is inadequate access to sanitation, sewage is very easily able to contaminate streams and rivers.

large sewage treatment facility in the countryside

Lack of government funding and support

Funding for sanitation facilities, or sewage pollution prevention and clean up is an underfunded area. Governments often de-prioritise this issue in favor of other - more headline grabbing - issues (issues like plastic pollution for example). 

👉 In the US for example it was found that between 2005 and 2019, only 6 million USD was allocated to dealing with ocean sewage pollution.

Lack of scientific research

Another reason that sewage pollution is deprioritised in favour of other forms of pollution is the lack of large scale studies that assess the impact of sewage contaminants on aquatic environments.

The issue isn’t isolated to developing countries

We’ve already touched on how impoverished communities tend to be the most vulnerable to issues of sewage pollution and improper sanitation, however, the issue is certainly not isolated to these regions alone. In fact, sewage pollution is becoming a growing problem in a number of developed nations too. 

England in particular has made headlines over the last few years for the growing problem it faces when it comes to sewage pollution and the effects on England’s rivers and beaches.

Why is sewage an issue in England?

It’s been uncovered that there were over 400,000 discharges of raw sewage into rivers in England and Wales in 2020 alone. And in 2022, dozens of beaches were shut off to swimmers due to the presence of high levels of toxic waste. But what’s causing these issues? 

In order to understand why sewage has become such an issue in England in recent years, we first need to understand a little bit about the UK’s sewage system.

youtube screenshot

The history of England’s sewage system

It was Sir Joseph Bazalgette who designed London’s modern day sewage system. Officially opened in 1865, the system was one of the world’s largest engineering works at the time, with over 1,100 miles of street sewers. 

After the construction of the sewage system in London, local authorities began to build their own, and by 1945 there were around 1,400 sewage companies operating in England and Wales. These were merged to create ten regional water authorities in 1973 under the Water Act.

After this point investments fell rapidly - in 1974 3.5 billion GBP was put towards England's sewage system, however by 1985 this had fallen to 1.8 billion.  It wasn’t long after - in 1989 to be exact - that the sector was privatized. Now England and Wales’ sanitation system is privately owned and run by 32 different companies.


The privatization of the system has led to a situation whereby water companies are incentivised to make sufficient profit. This means attracting investment and income, while also running a public service. It’s a difficult balancing act. And the situation is only getting harder. As the population of the UK continues to grow and climate change results in increased rainfall, England’s sewers are struggling to keep up with demand. 

In the UK, regulators set limits on how much sewage these private companies are allowed to release. This is permitted in exceptional circumstances such as when the sewage system becomes overwhelmed by an increase in rainfall. The release is intended to prevent damage to equipment and property and is only allowed when water companies are already treating a sufficient volume of sewage (known as full to flow treatment or FtFT). 

However, it’s been found that these limits are often exceeded by the private water companies - something that can be subject to heavy fines where it’s found that the release has been under-reported or hidden from regulators. 

👉 Southern Water was fined 90 million GBP in 2021 for being found guilty of thousands of illegal discharges of sewage waters in rivers and coastal waters in England. Over a period of 6 years it dumped 21 billion liters of untreated sewage!

The problem of deregulation

Many place the blame for the current situation at the feet of the UK Government. Decades of deregulation and underfunding have left the UK’s sewage system overwhelmed and unable to cope. 

When Lizz truss served as the Environment Secretary for the UK she oversaw 235 million GBP in cuts to the UK’s environment funding. This included 24 million in cuts to monitoring services that help to ensure that the private water companies don’t dump sewage into the UK’s water bodies. Since these cuts were made, reports estimate that raw sewage dumps in England and Wales have doubled!

Widespread issue

The UK’s Environmental Agency announced major investigations into potential widespread non-compliance by water and sewerage companies at wastewater treatment works. The investigation is  currently underway, however the Environmental Agency has warned that such a major criminal investigation takes time in order to comply with legal obligations and requirements. 

Initial reports from within the Environmental Agency suggest the issue is not an isolated one and that in fact, illegal release of sewage is a widespread issue across England and Wales. 

The industry has become reliant on this often illegal activity to make profits and bonuses and to do this it needed the agency to let most of it go unpunished and unchecked.” - Ash Smith, Founder of Windrush Against Sewage Pollution.
youtube screenshot

What is the UK Government doing to prevent sewage pollution?

In addition to the investigations that the UK’s Environmental Agency is carrying out the EA is also working with water companies to step up protection of the UK’s water bodies and to prevent sewage pollution. 

In order to achieve this goal the EA has increased monitoring and transparency from the water companies. Event Duration Monitoring (EDM) allows water companies to continuously monitor storm overflows. This enables the Environmental Agency to monitor the performance of water companies and to understand where improvements are needed to England’s sewers and treatment works. 

👉 In 2016 only 800 overflows across the network were monitored. This had increased to 12,700 by 2021. 

The EA is also running a new programme requiring water companies to improve how they manage and monitor flows at waste treatment works. This will also result in investment for increased capacity at treatment works and storm tanks. 200 million GBP has already been set aside for improvements to be made between 2025 and 2030.

Legal action

We’ve already talked about how water companies found to be in breach of environmental laws will be subject to fines, however, the buck does not stop there - potential legal action for breaches may also include criminal prosecution which may result in imprisonment. 

👉 Since 2015, the EA has brought forward over 56 prosecutions against water companies, resulting in total fines upwards of 141 million GBP.

Overhaul of the sewer system

The UK Government has also announced an overhaul of the UK’s sewer system in an effort to tackle sewage pollution. In August 2022, the UK Government published the Storm Overflows Discharge Reduction Plan. This is a legal commitment under the Environment Act 2021

The main aims of the plan include that by 2032 water companies in England and Wales must:

  • Improve all storm overflows discharging into or near to designated bathing water;
  • Improve 75% of overflows discharging into high priority nature sites;
  • By 2050 this will apply to all remaining storm overflows regardless of location.

While the plan is undoubtedly a step in the right direction, some have criticized it for lacking in urgency and have called on the UK Government to do more to speed up the pace of implementation.

person standing over a storm drain in the street

Round up

Sewage pollution is a growing problem, and not only in developing countries but also in wealthy nations too. Decades of underfunding and deregulation, coupled with inadequate monitoring and the prioritization of profits means that sewage systems like the UK’s are unable to cope with the increased sewage flow. 

Sewage pollution is not as widely talked about as other forms of pollution such as plastic pollution or air pollution, however, it’s a significant issue and one that must be addressed. Thankfully, public outcry and an increasing awareness of the issue is forcing governments to act and to implement the changes needed to protect our water bodies.

What about Greenly? 

At Greenly we can help you to assess your company’s carbon footprint, and then give you the tools you need to cut down on emissions. Why not request a free demo with one of our experts - no obligation or commitment required. 

If reading this article has inspired you to consider your company’s own carbon footprint, Greenly can help. Learn more about Greenly’s carbon management platform here.

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